Saw chain



Oct. 20, 1953 GOMMEL I 2,655,958

SAW CHAIN Filed Feb. 19, 1951 INVENTOR. DELI/7 1?. GOMIAEL ATZUFNEK Patented Oct. 20, 1953 .SAW CHAIN newer mel, I a lis, "Ind" .assignori "byJmesne assigiunents, to 'Bol g warner Cor-1101 ration, Chicago, R1,; a. corporation of Illinois Application Eebrnary 19, 19.51,;Serial No.;2=11;,ll41

5' Claims. 1.

T e Present invention relates to ,a .saw chain. and the primary object. of the invention .is to .provide a chain having cutters of improvedcharacteristics, whereby the tendency .of previously.- known chainsto wanderirom the .optimum lateral confines .ojf thekerito be out will be .substan tially, "if not, completely, overcome. .A further object of the invention is to provide .aputter-can ryinglinkior asaw chain so designed that the portions of,- the .cutting edge disposed on opposite sidesiofthe plane .of the .linkbody and actually at. work during operation of the chain, will heequalinlength. .To that .end, I providea link having .a cutterv or tooth .proj eating. from the .link body and deflected laterally intone direction from that plane, said toothsincludingjalso a portion, Drojectinglaterally. in .theopposite-direction from the onter. .end .of the deflected .nortion, traversing he plane, or the linkbodx, ;-and having an extent, laterally .in the opposite direction from said plane, .eoual, to, theemaximumsdefiection of the first-mentionedv portion increased :by the controlled depth .of .cut of, the deflected portion.

.Eurtherobjects of theinvention; will appear as the description i proceeds.

fIothe accomplishment of the above and; related objects, my invention may be embodied-in the .iorm illustrated in the accompanying :drawin s, attention beingcalledto the fact, however, that. the drawings ,are illustrative .only, andthat chan e may he made intthe specific-, constnuction illustrated :and describedj so, long 5&8 the Scene of \the appended claims-is not violated;

Fig. l ,is a side--.e1enation of -a .fragment ofia chain constructed, in-accordance with theqpres- .ent inizentionand shewnin cooperative relation with adriizing sprocket;

Fig. 2 is an enlarged.- -plan; view "of 2a cuttercarrying link constructed :in.accordance with-the present invention;

.Ei .3. is a. side elevationofsuch a link, shown in cooperative relation with a tooth a driving sprocket;

Fig. .4 is a front elevation thereof; and

Fig. 5 is an enlarged, fragmental front elevation showing the relation between the cutter tooth and-a depth gauge formed integral with the link in the preferred embodiment of my invention.

Referring more particularly tothe drawings, it will be seen that Thaveillus'trated a fragment of a chain zindicated generally by the reference numeral- :1 0-, and comprising center links H, each :of which is provided with .a tongue I2 adapted to, ride in the groove. of a. cormentionalchain saw cutter her, and. tohave idriwi ng association with..the teeth L3v oil-a driving: sprocket .1 4. .isaid center .linksarep'motally .connectedthroughchtten-carryingv link-s. J5 and intermediate linksjlli, as; shown. Each cutter-carryinglinkis provided on its inner. edge. with .a notch. .Ll, whose basejs adapted to be enga e by -.the.nose .llioi a tooth l3; and each side .link 16. isv provided. with a, notch .11 of corresponding-contour. Eachgtooth 1,3 .is iormed with a .driying snriace "t9 engageable with. the. trailing edge 'Zlhoia tongue 12,, and with a moresharply inclined suniace 21 adapted to .havetline contact thecur-ved lforwarn s'i'cle Wall. 22 of anotch 1.1 .or-thecorresponfihg Wall 22 ofra not-ch I l.

The hodyili of eachlink .'I5,.comnris esa planar plate formed, near-its .iorward. and ends, with-,periorationslli, 525 iiisnosed-onnarallel anes perpendicular to the plane of said body. At the forward. end of thehody, a .depth :gang .23.-.pro.- jects .in a direction generallypernendicular to theplanecomrnon.tothetaxes of .theneriorations .26, .zfig-endna. ,clltter tooth, indicated; generally-by the reference numeral .24 projectsrina generally correspimding direction .frorn .said. body. rneanthe rear .endthereoi, thedepthgaugeamcl the cutter tooth being separated. by: agullet 3-l As ismoreclearlyv illustrated inFigs. 4 and the tooth 1.4, .in the illustrated embodiment of the invention, comprises ashankizfl deflectedlaterfii -l ir m theplane-of the body 25;, .and a toe..28 carried at the enter end of the .shank 2-1.. and substantially perpendicular to the ,plane .of the body -25. Alternate cutter;-carrying links {5 in the chain have their .toothshanksifldeflected in opposite lateral directions. Near itsouterend.

" theshank. 2J-

beveled rearwardly and. toward the plane oi the. body 25. to define .a chisel edge .8.; dt le din a e f. th oe 2.8 s sim r y .bevheled toidefine a Chisel, edge '31l. In. the illustrated embodiment of the invention, the edges 32.9. and 0 m e n a arna e .e,to.d finea p in n I pres n ly believe thisarrangementto be optimum, but not essential,

T e p h au e .3, f cour w l e rmin 1 the depth to which the tooth 2 lwi1l-cntas itfis rawn. h ou h a ker fb nerme he work. The tQOtIlZA .is, of; course, formedto. providesui't able. e ie or the. ed es 2' a '3 n a cn d anoe with conventional practice, the up.- r d of he e as viewed n, Fi n ly n o the. i h while upper surface of the toe, as viewed in Fig,v '3,.".1fikewise inclines downwardly and to the right. The Ltoe itself is inclined slightly rdly and. to, the right "as viewed inFig. '4' so that, when the edge to is for-med, at the rake angle illustrated'in-F'ig.

median plane of the link body is greater than,.

rather than equal to, the transverse length of that portion of the toe disposed on the left side of the median plane. Ideally, the lateral extent of that portion of the edge 30 disposed on the right, or inner, side of said median plane will be equal to the lateral extent of said edge to the left,

or outer, side of said plane, increased by the dimension by which said edge lies beyond the outer end of the depth gauge 23. Referring more particularly to Fig. 5, it will be seen that the extent of the shank 2'! beyond the outer end of the depth gauge 23 is indicated by the character X. If the dimension from th median plane of the link body to the laterally outermost point on the shank 29 is represented by the letter Y, then the dimension from said median plane to the free tip of the tooth toe 28 should be X plus Y.

It has heretofore been proposed to construct teeth. of the general character of those here under consideration, for use in similar chains, with toes having equal lateral extents on opposite sides of the median plane of the link body for the purpose of balancing twisting stresses which are impressed upon the teeth during saw operation. Such a proposal, however, takes no account of the drag resulting from the cutting action of that portion of the sharpened edge of the tooth shank Which projects beyond the cut-depth-controlling depth gauge 23. As a consequence, teeth constructed in accordance with such prior proposal have a tendency to twist toward the outer boundaries of the kerf, gouging into the kerf side walls and causing the chain to run erratically, thereby unduly broadening or widening the kerf. According to the present invention, however, the

tooth toe will project toward the center of the kerf, beyond the median plane of the link body, to an extent sufiiciently greater than its outward projection, to compensate for the drag of the Working portion of the shank edge 29, thereby accurately balancing the strains encountered by the tooth on the opposite sides of such median plane, and overcoming the tendency 'of the tooth to wander from truly rectilinear travel.

I claim as my invention:

1. A saw chain cutter link comprising a planar body, a router tooth and a depth gauge projecting from said body generally in acommon direction, said tooth comprising a shank deflected laterally in one direction from the plane of said body and a toe carried at the outer end of said shank, a gularly related to said shank and traversing said plane to project laterally in the opposite; direction beyond said plane, said toe and said shank being sharpened at their leading ends,

the extent of said depth gauge being less than the extent'of said shank, and the degree of projection of said toebeyond said plane being equal to thedegree of deflection of said shank from said plane increased by the difference between the extent of said shank and the extent of said depth gauge. p

l ,2. A saw chain cutter link comprising a planar body formed, adjacent its front and rear ends, for

pivotalponnection, about parallel axes, with other l links in a, chain, a, depth gauge and a router tooth projecting from said body, generally in a common direction perpendicular to a plane common to said axes, said tooth including a shank laterally deflected from the plane of said body and a toe carried at the outer end of said shank and projecting therefrom laterally inthe opposite direction to traverse the plane of said body, the leading edges of said shank and said toe intersecting and being sharpened, and the lateral extent of the sharpened edge of said toe in said opposite direction beyond said body plane exceeding the lateral extent of the sharpened edge of saidv toe in the first-mentioned direction from said body plane by an amount equal to the difference between the extent of said shank and the extent of said depth gauge from said plane common to said axes.

3. A saw chain link-comprising a generally planar plate having a depth gauge and a cutting tooth formed thereon, said tooth including a portion extending from said plate generally in the direction of projection of said depth gauge but cfiset laterally from the plane of said plate, and a portion extending laterally in the opposite direction beyond the plane of said plate, the leading edge of said tooth being bevelled to a chisel edge, said first-named portion projecting beyond the free end of said depth gauge, and saidlastnamed tooth portion having a lateral extent beyond said plane substantially equal to the maximum offset of said first-named tooth portion, increased by the dii ference between the projection of said first-named tooth portion and the projecticn of said depth gauge.

4. In a saw chain, a link having a generally planar body and formed to provide a tooth having a portion deflected laterally from the plane of said body and a portion extending laterally oppositely from the outer end of said first-mentioned portion and traversing said plane, and means limiting the depth of cut of said lastnamed portion, the degree of projection of said last-mentioned portion beyond said plane being substantially equal to the maximum deflection of said first-mentioned portion increased by said depth of cut. e

5. A saw chain cutter link including a body formed to provide a depth gauge and an L -shaoed tooth comprising a planar shank inclined to one side of the plane of said body, and a planar toe carried at the outer end of said shank and substantially perpendicularly traversing the plane of said body, said toe lying beyond the outer end of said depth gauge, the forward edge of said toe, and the forward edge of said shank beyond said depth gauge, being sharpened to a chisel edge, and the effective cutting portions of said chisel edge, one of which portions is defined by the for ward edge of said toe and the forward edge of said shank beyond said depth gauge and disposed at one side of said plane and the other of which portions is defined by the forward edge of said toe disposed at th opposite side of said plane, being equal. p

DEWEY E. GOMMEL. v

References Cited in the file of this patent UNITED STATES PATENTS Number Name 2,326,854 Hassler AugPE IQQ 2,508,784 Cox May 23 1950 2,515,550 Ciba July is" 1950 2,558,678 Garrett June 26, 1951 

